The present invention relates to devices for the stripping, crimping and cutting of coaxial cable. More particularly, the present invention relates to a tool whereby all three functions can be carried out through the use of a single tool.
With the phenomenal growth of cable television, the use of coaxial cable has grown accordingly. Coaxial cable is generally constructed of a single inner copper conductor having an inner insulation, normally consisting of a formed plastic material such as polypropylene foam surrounding the conductor, and a very thin aluminum ground shield surrounding the inner insulation. A tough metal braid surrounds the shield in order to protect the shield and to provide further shielding for the inner conductor. The braid is normally made of a large number of thin wires twisted together along the length of the cable. The cable further includes an outer insulation or jacket which is normally made of polyethylene.
As with all electrical cables, in order to terminate the end of the cable to an electrical connector, the end of the cable must be stripped down to the inner conductor. With ordinary cable, which is normally an electrical conductor surrounded by insulation, stripping the insulation from the conductor does not present much of a problem. However, due to the complex structure of coaxial cable, difficulties have been encountered.
Solder-type end connectors for coaxial cable are well known and typically comprise a two piece arrangement with which the cable is first stripped in two levels: one to expose the shielding braid and the other to expose the center conductor of the cable. One piece of the fitting is slipped over the stripped end with the braid soldered at one position and the center connector soldered at another position. The second piece of the fitting has a female thread for attachment to a male fitting. A substantial limitation of this type of connector is that the solder joints may not be properly made or may later deteriorate because of the environment in which the connector is used. A solderless, compression-fit end connector has been developed.
Another problem with the attachment of end connectors to coaxial cable is that a technician must use one tool for stripping the coaxial cable, then set that tool down, and then pick up a different tool, or tools, for end connector attachment. The pliers-type stripping/crimping tools used with single conductor wire are unsuitable for both two-level stripping of coaxial cable and attaching compression fittings.
In the past, various U.S. patents have issued relating to devices for the stripping, crimping and/or cutting of such coaxial cable. For example, U.S. Pat. No. 4,558,584, issued on Dec. 17, 1985 to R. W. Myers, describes a combination cable crimper and cutter. A frame mounts on a piston for reciprocating axial movement. A reciprocating drive is connected to the piston. A pair of cable-crimping jaws is pivotally mounted on the frame and connected by links to the piston. A cutter anvil is mounted on the frame adjacent one of the jaws. A cutter is mounted on the jaw in cable-cutting relation to the cutter anvil.
U.S. Pat. No. 4,625,386, issued on Dec. 2, 1986 to Z. Bieganski, teaches a combination tool for carrying out the operations necessary to connect a telephone jack to the appropriate cable. Initially, the cable is cut to a desired length using cutting blades provided on the tool. Stripping of the insulation sheath from the cable is carried out by stripping blades also provided on the tool. A punch and dye crimping set is used so as to crimp the jack onto the cable.
U.S. Pat. No. 4,932,091, issued on Jul. 12, 1990 to J. A. Krzyzanski, teaches a tool for the attachment of a solderless, compression-fit end connector to the end of a coaxial cable. A manually lever-operated piston within the tool forces the components and the cable together so as to lock a connector to the cable and to provide a sealed chamber in which the braid connection is made. The connector attachment mechanism is located at one end of the tool. A two-level coaxial cable stripper is located at the other end of the tool.
U.S. Pat. No. 4,934,219, issued on Jun. 19, 1990 to D. B. Edwards, teaches an improved apparatus and method for stripping insulation from a coaxial cable for the purpose of placing the cable in a condition to be terminated to a connector. The apparatus is in the form of a hand tool which includes a single spring biased blade and a plurality of boreholes of different diameters adjacent to the blade. The coaxial cable is inserted in a first borehole where the outer insulation is stripped by the blade. The cable blade is then partially flared out and the cable is placed into a second borehole having an annular shoulder. This causes the blade to be peeled back thereby exposing the inner insulation which is then stripped by the blade.
It is an object of the present invention to provide a tool which carries out the stripping, crimping and cutting of coaxial cable.
It is another object of the present invention to provide a tool whereby a compression-fit end connector can be attached to the end of a coaxial cable.
It is a further object of the present invention to provide a tool whereby the coaxial cable can be effectively stripped by a two-level coaxial cable stripper.
It is a further object of the present invention to provide a tool whereby a coaxial cable can be effectively cut.
It is still another object of the present invention to provide a tool whereby the actions of crimping, stripping and cutting can be carried out in an easy and efficient manner.
It is a further object of the present invention to provide a tool which is easy to use, relatively inexpensive and easy to manufacture.
These and other objects and advantages of the present invention will become apparent from a reading of the attached specification and appended claims.
The present invention is a tool for coaxial cables comprising a body having a nose portion with a slot formed therein of a size suitable for receiving a connector of a coaxial cable therein, an arm pivotally connected to the body and movable between a first position outwardly of the body and a second position adjacent to the body, a crimper member slidably positioned in the body and having an end facing the slot, and a stripper member positioned within the body. The arm has a knife member affixed thereto. The crimper member is movable into the slot when the arm is moved from the first position to the second position. The body has an opening adjacent to the stripper member.
In the present invention, the arm includes a cam member which is rotatably mounted in the body. The cam member has a finger extending outwardly therefrom. The finger abuts the crimper member so as to move the crimper member toward the slot as the arm moves toward the second position. A handle is connected to the cam member and extends outwardly of the body. The cam member also includes a strut which is integrally formed therewith and extends radially outwardly therefrom. The handle has a channel therein. The strut is fixedly received within the channel. The knife is formed on the cam member and extends along the strut such that the sharp edge of the knife member faces the body. The body also has a knife member affixed thereto so as to have a sharp edge facing the sharp edge of the knife of the cam member. The sharp edge of the knife of the cam member is movable toward the sharp edge of the knife member of the body so as to cut a coaxial cable placed therebetween.
In the present invention, the crimper member comprises a plunger resiliently mounted in a channel formed interior of the body. The arm urges a portion of the plunger outwardly of the channel and into the slot when the arm moves from the first position to the second position. The slot is formed so as to open on one side of the body. The nose portion has a retainer edge at an end thereof so as to retain the connector of the coaxial cable within the slot. The slot extends longitudinally along the nose portion of the body.
In the present invention, the stripper member comprises a plug member slidably positioned in a channel of the body. The plug member has an interior opening. The plug member has a protrusion extending outwardly of the body. A knife element is affixed to the plug member so as to have an edge extending across the interior opening. The interior opening is of a size suitable for receiving the coaxial cable therein. The edge of the knife element is suitable for stripping a sheathing from the coaxial cable. A spring is positioned in the channel of the body so as to resiliently urge the protrusion outwardly of the body. The arm has a portion contacting the protrusion when the arm member is in the second position. This arm urges the plug member into a position whereby the interior opening of the plug member is aligned with the opening of the body.